Background  The Unmanned Aerial Vehicle (UAV) remote sensing provides a new supporting technique for soil and water conservation monitoring. However, for the practical use in soil and water conservation monitoring for construction projects, this technology is still at its beginning age and no uniform application methods or standards have been set up. The purpose of this work is to establish a method of soil and water conservation monitoring based on the UAV remote sensing technology, aiming at increasing the monitoring precision of UAV sensing technology and providing technical support for control soil loss in the construction projects.

Methods  The established method is divided into three parts: the acquisition of basic data, the extraction of monitoring information and the application of information in monitoring work. First, the acquisition of basic data was carried out by UAV with GPS, IMU and specific sensor, and the raw data processing was conducted by Agisoft Photoscan Professional to obtain the Digital Elevation Model (DEM) and Digital Orthophoto Map (DOM) results. Second, the extraction of monitoring information was based on the DEM and DOM results by software ArcGIS. The information extracted from DEM and DOM results generally includes the land cover type, the location, length, area and volume for a specific object and the reconstruction of a 3D model for the project area. Finally, according to the criterion, extracted information, and specification, the practical monitoring work was proceeded, in which the data include the monitoring of land disturbance, the use and disposal of soil, soil and water conservation measures, soil loss and soil and water conservation effects.

Results  The established method was applied to a specific construction project for soil and water conservation monitoring test with a UAV of Phantom 4 Pro. In our test, the relative flight height was 129 m, and the aerial coverage area was 7.15 hm². Horizontal resolution of the DEM and DOM results were 0.051 and 0.206 m, respectively. It was indicated that the areas of the typical temporary disposal area, production and living area 1, 2 and 3 was 7 414.23 m², 1 818.57 m², 2 371.8 m² and 1 851.94 m², respectively. The volume of the temporary disposal was 72 626 m³ without temporary covers. Compared to the traditional monitoring methods, the established method not only saved time more than two third, but also avoided accident errors.

Conclusions  The established method can be used in practical soil and water conservation monitoring for construction projects, and it is simple and practical. More importantly, it can improve our technical skill to apply UAV remote sensing technology into real soil and water conservation monitoring work, as to give strong technical support for soil and water conservation in construction projects.